The present invention relates to an atomization device for a refrigeration system and more particularly relates to a device for efficiently converting liquid refrigerant from the condenser to a super saturated vapor.
A typical vapor compression refrigeration system includes a compressor, a condenser an evaporator and an expansion device arranged to transfer heat energy between a fluid in heat transfer relationship with the evaporator and a fluid in heat transfer relationship with the condenser. Refrigeration systems of this type are widely used in applications such as ice machines, automotive air conditioners, cascade systems and refrigeration systems for walk-in coolers. Some such systems may be reversible systems and are designated as heat pump systems often used for residential heating and cooling.
In the refrigeration cycle, the compressor directs a hot, gaseous refrigerant to the condenser. Heat energy is rejected at the condenser and heat is absorbed at the evaporator. Refrigerant from the condenser passes through an expansion valve where the liquid is atomized and evaporated. The expanded and atomized liquid is then directed to the evaporator coil. Cooling occurs as heat is absorbed by the refrigerant. Various types of expansion devices can be found in the prior art. For example, U.S. Pat. No. 4,263,787 shows an expansion device having a piston slidable between first and second positions within a valve body. In the first position, the piston meters refrigerant flow there through and in the second position the piston allows refrigerant to flow unrestricted through the device. Means are disclosed for adjusting the throttling of the refrigerant through the device when it is acting as an expansion device.
Another piston expansion device is shown in U.S. Pat. No. 5,041,257. This patent shows expansion device having a movable piston having a first end surface adapted to engage a valve seat to close the valve when the piston is in the first position. When the piston is disposed in the second position, the piston has a passage there through which interconnect ports.
Yet another expansion valve assembly is shown in U.S. Pat. No. 4,911,404. Again, a piston is mounted in a body and is actuated by a stepper motor. In other patents disclosing expansion devices having a movable piston include U.S. Pat. No. 5,894,741. Thus, while there are various expansion devices which utilize a piston that can be found in the prior art, most are complex having numerous components and requiring more elaborate sealing and flow passageways.
Accordingly, it is the object of the present invention to provide a simple expansion or atomization device which will effectively atomize liquid refrigerant to provide greater heat transfer efficiency in the evaporator. It is yet another object of the present invention to provide an economical, reliable and adjustable atomization and expansion device for refrigerants.
The above and other objects are achieved by an expansion device which has a housing having an inlet port receiving liquid from the condenser. The housing has multiple outlet ports which direct supersaturated vapor to the evaporator or to an intermediate receiver. The liquid from the condenser is received within the body of the atomizing valve in the housing. The body of the valve is provided with a plurality of orifices or nozzles at spaced-apart locations along its length. A piston is reciprocable within the valve body and as the piston moves in one direction or the other, will either communicate the orifices or nozzles with the liquid or close off the nozzles or orifices and reduce the volume of the liquid-receiving valve chamber.
Preferably the position of the piston is controlled by a stepper motor operated by a temperature sensor on the evaporator coil. As the temperature decreases, the piston will move in a direction to decrease the volume of the valve chamber. The liquid entering the valve chamber will expand and vaporize and exit the valve body through the orifices or nozzles, the number of which will be determined by the position of the piston within the valve body. The expansion device of the present invention will significantly reduce compressor failure as a result of liquid carry-over.